Is there a reference here or in the archives to time periods/dates for general features on high-end Italian-made bikes?

I'm essentially trying to date a frame that has some features like a clamp-on front derailer, over-the-bb cable routing and no serial # (doesn't look scratched out or repainted, just not there at all.)

Is there a consensus here about when, for example, cable routing changed or braze-on's were used or is that just a crap-shoot depending on way to many variables to accurately pin down any general ideas about when a frame was made?

This is probably WAY to general but what the hell...I'm stuck!